1. Field of the Invention
The present invention is a tool for applying tension to a tubing string within a well bore. The tool or apparatus allows tension to be applied to the tubing string without the requirement for equipment to raise and lower the tubing string at the well surface. Also, methods are disclosed for using the tool to complete wells.
2. Description of the Prior Art
Most producing oil and gas wells have a well bore defined by a casing string and tubing disposed within the casing. A packer generally is used to seal between the tubing and casing and to direct formation fluid flow through the tubing to the well surface.
The tubing string is frequently placed in tension between the packer and the surface to minimize tubing buckling from pressure and temperature changes, to minimize contact between the tubing and a pump rod, and to allow unrestricted wireline operations through the tubing bore. Also, tension may be applied to the tubing to evenly distribute the weight of the tubing string between a tubing hanger at the well surface and the downhole packer.
Tension is commonly placed on the tubing string by engaging the lower end of the tubing with a packer previously installed downhole in the casing, raising the tubing by conventional drawworks until the desired tension is shown on a weight indicator and then setting slips to secure the tubing at the well surface. The sequence of spacing out the tubing at the well surface usually requires the use of one or more short sections of tubing called pup joints. Also, the surface blowout preventers must be removed for considerable lengths of time while installing the pup joints and setting the slips at the well surface. The present invention reduces the amount of tubing manipulation previously required at the well surface to place a tubing string in tension. The present invention can be used in various types of wells including oil and gas, steam and water injection, and geothermal wells.
U.S. Pat. No. 2,836,250 to C. C. Brown discloses a sleeve slidably disposed within a housing used to set a packer. Hydraulic fluid pressure acts on a piston carried by the sleeve to extend the sleeve relative to the housing forcing slips to engage the inner wall of the casing. U.S. Pat. No. 2,836,250 does not disclose nor teach using a sleeve and housing to apply tension to a tubing string.